Apparatus for liquefying gases with a low boiling-point.



G. HILDEBRANDT.

APPARATUS FORLIQUEFYING GASES WITH A LOW BOlLlNG POINT.

APPLICATION FILED JAN. 9, I911.

Patented Sept. 26, 1916.

34119 e/nlo's,

6.192 Zdebmndl'.

sa'aans PATENT curios.

GOTTHOLD HILDEBRAND'I, OF SPANDAU-TIEFWERDER, NEAR BERLIN, GERMANY,

ASSIGNOR, BY MESNE ASSIGNMENTS,

TO AMERICAN INDUSTRIAL GAS COM- PAN'Y, OF NEW YORK, N. Y., A CORPORATIONOF YORK.

APPARAYID 'S FOR LIQUEFYING GASES WITH A LOW BOILING-POINT.

, To all whom it may concern l the discharge aperture.

Be it known that I, ,Go'r'rHoLD HILDFP BRANDT, engineer, citizen ofGermany, subject of the King of Prussia and Emperor of Germany, residingat Spandau-Tiefwerder 2%, near Berlin, in the Kingdom of Prussla andEmpire of Germany, have invented new and useful Improvements inApparatus for Liquefying Gases with a Low Boiling-Point, of which thefollowing is a specification.

The liquefaction of gases with a low boiling point has heretoforegenerally been effected only by the'regenerative method in-' dicated bySiemens in the year 1857 which consists in compressing, cooling andexpanding these gases such for example as-nitrogen, oxygen, hydrogen andso forth, and conducting the cooled gases thus obtained in countercurrent to fresh compressed gases, thereby producing an interchange ofheat, which ultimately results in the desired liquefaction. Inaccordance with Various systems this expansion has takenplace either ina counter current system or pipes or in. open cavities. This method haspresented the defect that thediquefying period occupies a considerabletime as the greatest cooling which is theoretically possible cannot bereached owing to the apparatus employed, because with this method ofexpanding, the frictional resistances of the counter current? system. ofpiping do not permit of fullyutilizing the energy supplied in. thecompressed gases, and by this method it is impossible to utilize thekinetic energy of the gas molecules obtained by expanding to such anextent that their pressure falls below' It is well known that compressedgas-y when it issues through an aperture into a space of less pressureand'escapes'with an increased kinetic energy, is cooled close to Thiscooling (called by Travers velocity cooling) has not been 1 used up tothe present time for the liquefication or' the separation of gasalthough it represents a very rich source of cold because this coolingexists only immediately after passing through the aperture anddisappears at a relatively short distance from the aperture, thevelocity of the stream, of gas being reduced by friction caused by itsimpinging against the wall of the vessel v Specification of LettersPatent.

Application filed January 9,

- ually increasing evolved-by such differences that the expansion partof Fig. 4.-

The nozzle C has velocity increases in the gas has fallen to 800 13111.,that *is to say to a Patented Sept. 26.

Serial No. 601,614.

into which it flows. Therefore in order to produce low temperaturescooling by utiliz- 1ng theJoule-Thompson effect only was applied whichis the result of the internal work only caused by the expanding gas.

have now succeeded in utilizing the velocity cooling for the continuouscooling and liquefication of gases and the separation of gas mixtures byapplying a particular form of expanding nozzle and the space. into whichthe expanding gas stream flows.

The apparatus hereinafter described is deslgnedto avoidthe loss ofenergy which is present in existing systems, and to this end theexpansion is effected in a space of gradcross-sectional area, for 7Ostance in one ormore nozzles of the type Laval, the smallest andlargest, cross sections of these nozzles presenting of the gasin thenozzle belowthe pressure of the atmosphere.

In the accompanying drawings Figure 1 represents alongitudinal sectionof a simple form of apparatus embodying this invention; Fig.2 is formwith a device for transferrin to the compressed gas; Figs. 3 andsent'similar views of another form'of being ience I1n illustration.

In the "drawings the preliminarily cooled f .f compressed gas. passesthrough the tube A expansion valve" B .into the nozzlexO.

a conical form of grad-v and ua'lly increasing sectional area.

f Taking the admission pressure of the preliminarily cooled compressedgas by way of I example as 100 atmospheres equal to 100' kg. per squarecm. and the admission apertureA-bf the nozzle C as l'squar'e 'mm. thecorrespondence with the'diminishing pressure in the nozzle. The

molecules then separate more and jmore' fromgeach otherand when thewidth-of the opening of the nozzle has to say presents a who totheadmission aperture of 1 to 1250, the pressure ofg/ reached 40mm. that isgramsper square" min-us fsomewhat'more than one-fifth o fihere.

an atmoschamber itself may fall .75

a similar View of another 80- the cold '5 4 repre ff I the Iapparatuswith an enlarged inlet snace,a

broken off fo conven- 85 ressure. f- 1 05 g It is therefore importantthat the Q I I ower aperture as compared with the upper I 'sponding heatequivalent disappears and as the process takes place almostadiabatically' this is only at the cost of the temperature ofa part ofthe expanded gas.

Rankine has already shown that the adiabatic expansion of superheatedsteam causes its condensation and in the Laval nozzle a highly heatedliquid is converted by cooling into a mixture of liquid and vapor. The

' present invention is based on similar physical principles. In thefirst place the specific heat of the expanded gas and the partitions isconsumed to cover the expenditure of heat, then as soon as the-pressurefalls below atmospheric pressure a part of the gas mustyield up itslatent heat, that is to say it liquefies, but at first these liquidparticles retain the velocities of the former gas mole-,

' cules exactly like the steam condensate of a v special air pumps.

cause the nozzles to open into a collecting steam generatorfeedinjector. It is an advantage of the system that this reduction ofpressure below atmospheric pressure takes place merely by an increase ofthe velocity of'the molecules .without the necessity for Thus it ispossible to nozzle E (Fig. 2) or a collecting tube and to convert thevelocity into pressure without risk of the liquid obtained againvaporizing.

It is of course necessary by suitably forming the nozzle to prevent anyfriction of the gas at the nozzlewalls when the-gas pass--- ingtherethrough is under higher pressures. For this purpose the portion ofthe nozzle near its inlet end is enlarged, as diagrammatically showninFigs. 3 and 4. At the a u inlet of the gas the ,expanslon reservoir isenlarged to a cylindrical space G so that the jet of the gas issuingfrom the valve B or the like does not touch the walls. In consequence ofinjector action or suction avacuum is formed at the outer ends H of theenlarged space G, which assists the cooling action. A purely adiabaticexpansion is not possible because the metallic nozzle and the supplypipe conduct their heat to the expanded gas. In'order to. avoid thisdefect the cold imparted to the expansionvalve B is transferred by adevice shown in Fig. 2 directly to the compressed gas before theexpansion and not only cools it but its property of being a poorconductor of heat takes place durin nozzle with a gas envelop which is apoor conductor. With this object the nozzle C is made of a substancewhich is a good conductor such as copper, and inserted in a vessel Dwhich receives the cooled compressed gas from the inlet (A). From thevessel D the cooled compressed gas is conducted to the expansion valveB, from which it is expanded into the conical nozzle 0. This apparatusis likewise utilized for sepa rating any foreign gases with a highboiling point from the compressed gas to be liquefied before it canexert any harmful eiiect by stopping the valve. Thecooling which theexpansion process in the copper nozz e is consequently transferreddirectly to the compressed gas before its expansion and gradually coolsit sufliciently to cause the foreign substances of higher boiling pointas for instance watervapor, carbonic acid, etc., contained in thecompressed gas to be precipitated as liquid or solid bodies which can bedrawn ofi through a special pipe F in the bottom of the vessel 1).

1 f Having now described invention what I claim and desire to secure byLetters Pat- .ent'of the United States is: v

. 1. lncan apparatus for liquefying gases with a low boiling point, aconduit for the compressed and cooled gas, and an expan sion nozzlearranged to receive the gas from said conduit and to expand and liquefythe same, said expansion nozzle having a crosssectional area whichgradually increases substantially as the square of the distance from thepoint of admission of the gas, the

ultimate dimensions of said area being small as compared to the lengthof the nozzle, and said nozzle being so proportioned as to ef- 'fectvelocity cooling of the gas expanding therein.

2. In an apparatus 'for liqu'efying gases with a low'boiling point,a-conduit for the compressed and sealed gas;}and an expansion nozzlearrangedto receive the gas from said conduit and to expand and liquefythe same, said expansion nozzle having an enlarged portion at itssmaller end and being of gradually increasing cross-sectional area andbeing so proportioned as toefiect velocity cooling of the gas expandingin said nozzl'e of gradually increasing area.

3. In an apparatus for liquefying gases with a low boiling point, aconduit for the compressed and cooled gas, an expansion nozzle arrangedto receive the gas from said conduit and to expand and liquefy.the'same, and a vessel surrounding said nozzle for receiving the gas inits passage from said coni ice 7 duit to the inlet ofthe nozzle, saidexpan- I sion nozzle being of gradually increasing cross-sectional areaand being so proportioned as; to effect substantially adiabatic 65 isutilized for surrounding the expansion expansioniegt. the gas therein.

-, of gradually increasin and cooled gas,

4. In an apparatus for liquefying gas with zle of gradually increasingcross-sectional area, having a substantially smaller crosssectional areaat its inlet than its outlet, and being so proportioned as to effectsubstantially adiabatic expansion, said nozzle being in connection withsai expansion valve, the admission aperture of said nozzle having asubstantially smaller cross-section than the discharge aperture, and theconical nozzle being proportioned to effect velocity cooling of thegases expanding therein.

a low boiling point, an expanslon 1102- cross-sectional area 7 6. In anapparatus for liquefying gases with a low boiling point and inparticular atmospheric air and hydrogen gas the combination of a conduitfor the compressed and cooled gas, an expansion valve at the end of saidconduit, with a conical nozzle of gradually increasing cross-sectionalarea in connection with said expansion valve, the admission aperture ofsaid nozzle having a substantially smaller cross-section than thedischarge aperture, a part of said conduit being arranged in aheat-conducting contact with the portion of said nozzle near the saidexpansion valve.

In testimony whereof I have hereunto set my hand in presence oftwosubscribing Witnesses.

GOTTHOLD HILDEBRAND T.

Witnesses WOLDEMAR HAUPT, HE RY HASPER.

